To provide a projection type display device capable of efficiently using light emitted from a lamp with a simple constitution and using a light source free from uneven luminance.

The light from the light source 1 is directly emitted to a condenser lens 4, and also, the light is emitted to an elliptic reflection mirror 2 and a flat reflection mirror 3. The outgoing light is reflected by the elliptic reflection mirror 2 and the flat reflection mirror 3, finally, the light is emitted to the condenser lens 4 on the same optical path as that of the light directly emitted to the condenser lens 4. Then, all the light is nearly collimated by the condenser lens 4 and an incident Fresnel lens 12, thereafter, the light is made incident on a liquid crystal panel 7. The light from the condenser lens 4 is received by the liquid crystal panel 7, and then, the light is optically modulated by a video signal, then, the optically modulated light is enlarged and projected through a projecting lens 11.